Public domain image by the National Center for HIV/AIDS, Viral Hepatitis, STD and TB Prevention www.cdc.gov The number of annual new HIV infections in the US fell by 18% overall since 2008, offering evidence that prevention and treatment efforts are having an impact, according to data from the US Centers for Disease Control and Prevention released on Tuesday to coincide with presentations at the 2017 Conference on Retroviruses and Opportunistic Infections in Seattle. A closer look at the data, however, shows some notable differences across demographic groups and geographic regions.